Pediatric pulmonology
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Pediatric pulmonology · Jan 1991
Pilot study for the development of a monitoring device for ventilated children.
Airway pressure and air flow were measured at the endotracheal tube in 13 children on a variety of ventilators. These signals were stored for analysis on a computer. Further data sets were obtained after 24 hours or following major interventions. ⋯ There was minimal interference with patient care. This pilot study demonstrates that changes in respiratory mechanics can be displayed safely and easily in ventilated patients using resistance and compliance loops. Further work is necessary to confirm the usefulness of real time of these displays.
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Pediatric pulmonology · Jan 1991
Cold air challenge of airway reactivity in children: a correlation of transcutaneously measured oxygen tension and conventional lung functions.
For pharmacological challenges, a correlation between the induced changes of the transcutaneously measured oxygen tension (PtcO2) and of conventional pulmonary function tests (PFTs) has been documented. We performed a 4-minute cold air challenge (CACh) in 17 children with bronchial asthma under continuous monitoring of PtcO2, and correlated observed changes with CACh-induced alterations of conventional PFTs. ⋯ Changes of FVC, PEF, and Vmax50 correlated significantly as well. PtcO2 can complement or substitute for conventional PFTs in assessing the response to CACh in children.
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Pediatric pulmonology · Jan 1991
Inspiratory time and pulmonary function in mechanically ventilated babies with chronic lung disease.
To learn if increasing inspiratory time would improve pulmonary function in mechanically ventilated babies with chronic lung disease, we measured lung mechanics and alveolar ventilation at three inspiratory times: 0.4, 0.6, and 0.8 s. Nine babies were studied. Their mean birth weight was 875 g (range, 570-1,100 g), gestational age 27 (24-34) weeks, and age 7 (4-12) weeks. ⋯ At 0.6 s and 0.8 s, when compared to 0.4 s, significant increases occurred in tidal volume (10.4, 10.1, and 8.4 mL/kg, respectively), dynamic lung compliance (0.68, 0.68, and 0.53 mL/cmH2O/kg, respectively), and alveolar ventilation (6.0, 6.3, and 4.7 mL/kg/breath, respectively). Airway resistance, anatomical dead space to tidal volume ratio, and functional residual capacity were similar at the three inspiratory times. Our findings suggest that an inspiratory time greater than or equal to 0.6 s (compared to 0.4 s) increases the effectiveness of mechanical ventilation for babies with chronic lung disease.
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Pediatric pulmonology · Jan 1991
Airway pressures during crying: an index of respiratory muscle strength in infants with neuromuscular disease.
The purpose of this study was to assess the strength of the respiratory muscles in 12 infants with neuromuscular disease (age range: 0.17-2.08 years) by measuring the maximal inspiratory and expiratory airway pressures (Pimax and PEmax) during crying efforts. Infants were divided into two groups according to their respiratory history. Group A included six infants in stable condition without clinical evidence of respiratory abnormalities, and Group B included six infants with severe generalized muscle weakness and previous respiratory failure. ⋯ A positive correlation was found between PEmax and body mass percentile. No infant had hypercapnia at the time of the study, and Pao2 values in infants of Group B were significantly lower than those of Group A. These results suggest that measurements of airway pressures during crying may provide an index of respiratory muscle strength in infants with generalized muscle weakness.
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Pediatric pulmonology · Jan 1991
Effect of positive end-expiratory pressure on respiratory compliance in children with acute respiratory failure.
We studied the effect of positive end-expiratory pressure (PEEP) on the compliance of the respiratory system (Crs) in 25 children (age, 3 weeks to 10 years) requiring mechanical ventilation. Functional residual capacity (FRC) measurements were performed at 2 cm H2O increments, from 0 to 18 cm H2O of PEEP, and the FRC values were regressed versus PEEP. Static Crs, Crs/kg, and specific compliance (Crs/FRC) were calculated for each PEEP level. ⋯ We concluded that static respiratory compliance improves in most (but not all) children with acute respiratory failure when FRC is normalized. Static respiratory compliance reaches maximum levels at PEEP values that are close (but not equal) to those that result in FRC normalization. Thus, assessment of the effect of PEEP on compliance is required in individual patients.